1. Field of the Invention
The present invention relates to a hard-coated antiglare film, a polarizing plate and an image display including the same, a method for producing the same, and a method for evaluating the same.
2. Description of Related Art
In image displays such as cathode ray tube (CRT) displays, liquid crystal displays (LCDs), plasma display panels (PDPs), and electro luminescence displays (ELDs), hard-coated antiglare films are placed on the surfaces of displays to prevent a decrease in contrast caused by reflections of external light and image. Recently, improvements in image quality and contrast are progressing in LCDs, particularly LCDs used for television sets. One of the causes of decrease in contrast of LCD is a haze value of the hard-coated antiglare film placed on the surface of the display. To further improve the contrast, a hard-coated antiglare film with low haze value is required.
In the conventional hard-coated antiglare film with a relatively high haze value, there is a small difference in degree between fluorescent lamp reflection and face reflection. The fluorescent lamp reflection is a reflection of direct light and is a simple image with a high light quantity, and antiglare properties are judged by observing whether or not a reflected edge of an image is clear with naked eyes. On the other hand, the face reflection is a reflection of indirect light and is a complex image with a low light quantity. In this case, antiglare properties are judged by observing an extent of blur of an entire image with naked eyes. However, in the hard-coated antiglare film whose antiglare properties are suppressed to the fullest extent possible to realize a low haze value, designing to prevent both the two types of reflections typified by the fluorescent lamp reflection and the face reflection has been difficult. Furthermore, in the case where the surface unevenness is increased to improve antiglare properties while maintaining a low haze value, there is a problem in white blur in an oblique direction, that is, white blur is observed due to excessively intensive scattering of reflected light when the panel surface is viewed from the oblique direction. Generally, although an improvement in antiglare properties and an improvement in contrast or white blur are considered to have a contradictory relationship, various proposals have been made to obtain both these properties. For example, aggregates with three-dimensional structures formed of the particles present in an antiglare layer are being studied (for instance, see JP 2005-316413 A, JP 2007-264113 A, and JP 2007-249191 A). Further, an uneven shape on the topmost surface of an antiglare layer designed to prevent reflection and white blur is being studied (for instance, see WO 2006/0088202 A, and JP 2009-98657 A). These are merely studies of fluorescent lamp reflection, and studies to prevent face reflection or both the fluorescent lamp and face reflections have not been carried out.